Battery thermal management system, control method and electric vehicle

Abstract

The embodiment of the invention discloses a battery thermal management system, a control method and an electric vehicle, and belongs to the technical field of new energy. The system comprises a battery pack, a controller, a liquid inlet and a liquid outlet, a heat exchanger and a reversing valve body are arranged in the battery pack, and the heat exchanger comprises a first heat exchanger port and a second heat exchanger port; the heat exchanger is used for cooling or heating the battery pack; the controller is used for controlling the valve body gear of the reversing valve body based on the thermal management mode; wherein the liquid inlet under the cooling gear is connected with the first heat exchanger port through the reversing valve body, and the liquid outlet is connected with the second heat exchanger port through the reversing valve body; and the liquid inlet under the heating gear is connected with the second heat exchanger port through the reversing valve body, and the liquid outlet is connected with the first heat exchanger port through the reversing valve body. The flow direction of liquid in the heat exchanger is changed through the reversing valve body, the heating and cooling effects of the battery can be guaranteed, and the battery performance is optimized.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of new energy technology, and in particular to a battery thermal management system, a control method and an electric vehicle. Background Art

[0002] Electric vehicles have been promoted worldwide. In order to ensure the normal use of electric vehicles in all climate environments, battery thermal management heating and cooling functions are adopted to ensure that the battery operates in the best and most suitable temperature range.

[0003] In the related art, a liquid cooling and liquid heating solution is usually adopted, that is, high-temperature liquid is passed into the battery pack to achieve heating, and low-temperature liquid is passed into the battery pack to achieve cooling.

[0004] However, in thermal management design, once the liquid flow direction and inlet / outlet direction in the heat exchanger are determined, the battery area where the low-temperature / high-temperature liquid passes first has the best cooling / heating effect, and the battery area where the liquid passes last has a poorer cooling / heating effect. Since the battery temperature distribution trends are opposite in the two scenarios of high-temperature heat dissipation and low-temperature heating, the fixed liquid flow direction cannot perform differential cooling on batteries with different temperature distributions, resulting in the heating / cooling performance not being able to reach the optimal level at the same time. Summary of the invention

[0005] The present application example provides a battery thermal management system, a control method and an electric vehicle, and the technical solution is as follows.

[0006] On the one hand, an embodiment of the present application provides a battery thermal management system, the system comprising a battery pack, a controller, a liquid inlet and a liquid outlet, a heat exchanger and a reversing valve body are arranged inside the battery pack, and the heat exchanger comprises a first heat exchanger port and a second heat exchanger port;

[0007] The heat exchanger is used to cool or heat the battery pack;

[0008] The controller is used to control the valve body position of the reversing valve body based on the thermal management mode, and the valve body position includes a cooling position and a heating position;

[0009] Wherein, in the cooling gear, the liquid inlet is connected to the first heat exchanger port through the reversing valve body, and the liquid outlet is connected to the second heat exchanger port through the reversing valve body; in the heating gear, the liquid inlet is connected to the second heat exchanger port through the reversing valve body, and the liquid outlet is connected to the first heat exchanger port through the reversing valve body.

[0010] On the other hand, an embodiment of the present application provides a control method, which is used for the battery thermal management system, the system comprising a battery pack, a controller, a liquid inlet and a liquid outlet, a heat exchanger and a reversing valve body are arranged inside the battery pack, and the heat exchanger comprises a first heat exchanger port and a second heat exchanger port;

[0011] The method comprises:

[0012] Cooling or heating the battery pack by means of the heat exchanger;

[0013] Based on the thermal management mode, the controller controls the valve body position of the reversing valve body, wherein the valve body position includes a cooling position and a heating position;

[0014] Wherein, in the cooling gear, the liquid inlet is connected to the first heat exchanger port through the reversing valve body, and the liquid outlet is connected to the second heat exchanger port through the reversing valve body; in the heating gear, the liquid inlet is connected to the second heat exchanger port through the reversing valve body, and the liquid outlet is connected to the first heat exchanger port through the reversing valve body.

[0015] On the other hand, an embodiment of the present application provides an electric vehicle, which includes a battery thermal management system as described in the above aspects.

[0016] In an embodiment of the present application, a reversing valve body is additionally provided in the battery thermal management system, and the valve body position of the reversing valve body is controlled by a controller according to the thermal management mode to change the flow direction of the liquid in the heat exchanger, thereby achieving heating of the edge area of ​​the battery and then the center area of ​​the battery in the heating mode, and cooling of the center area of ​​the battery and then the edge area of ​​the battery in the cooling mode, thereby ensuring both the heating effect and the cooling effect of the battery, optimizing the battery performance, and improving the utilization rate of the battery energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A structural block diagram of a battery thermal management system provided by an exemplary embodiment of the present application is shown;

[0019] Figure 2 A schematic diagram of adjusting the flow direction of a liquid through a reversing valve body provided by an exemplary embodiment of the present application is shown;

[0020] Figure 3 A schematic diagram of the internal structure of a reversing valve body provided by an exemplary embodiment of the present application is shown;

[0021] Figure 4 A schematic diagram showing a method of adjusting the flow direction of a liquid by controlling a piston provided by an exemplary embodiment of the present application is shown;

[0022] Figure 5 A schematic diagram showing another exemplary embodiment of the present application for adjusting the flow direction of a liquid by controlling a piston is shown;

[0023] Figure 6 A schematic diagram of the structure of a flow rate regulating device provided by an exemplary embodiment of the present application is shown;

[0024] Figure 7 A flow chart of a control method provided by an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0026] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0027] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0028] It should be understood that, although the terms first, second, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first parameter may also be referred to as the second parameter, and similarly, the second parameter may also be referred to as the first parameter. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0029] First, the nouns involved in the embodiments of the present application are briefly introduced:

[0030] Battery Thermal Management System: (BTMS) is a system that specifically controls the temperature of battery packs or battery groups. Its purpose is to ensure that the battery operates within a suitable temperature range to protect battery performance, extend service life, prevent safety risks, and optimize the energy efficiency of the entire battery system. Optionally, the battery thermal management system may include temperature sensors, controllers, cooling / heating equipment, etc.

[0031] Battery cooling: Since heat is generated during the charging and discharging process of the battery, the internal temperature of the battery will rise. If the battery temperature is too high, it will damage the battery materials and even cause thermal runaway. Therefore, in order to prevent the battery from overheating, the battery needs to be cooled to ensure that the battery operates within an appropriate temperature range, thereby improving battery performance, extending battery life, and reducing safety risks.

[0032] Battery heating: In a cold environment, low temperature will reduce the battery's charging and discharging performance and available capacity. Long-term operation at low temperatures will shorten the battery's service life. Therefore, in order to prevent the battery from being at low temperatures for a long time, the battery needs to be heated to ensure that the battery operates within an appropriate temperature range, thereby improving battery performance, extending battery life, and reducing safety risks.

[0033] In the related art, in the battery thermal management system, the liquid flow direction and the inlet / outlet direction in the heat exchanger are fixed, which makes the battery area where the low-temperature / high-temperature liquid passes first often have the best cooling / heating effect, while the cooling / heating effect of the battery area passed last becomes worse.

[0034] In an illustrative example, taking the fixed flow direction of the liquid passing through the edge area of ​​the battery first and then through the center area of ​​the battery as an example, since the temperature of the center area (battery core) of the battery pack is usually higher and the temperature of the edge area is lower, although in the low-temperature heating scenario, the high-temperature liquid passes through the edge area of ​​the battery first and then through the center area of ​​the battery to achieve a better heating effect, but in the high-temperature heat dissipation scenario, the low-temperature liquid passes through the edge area of ​​the battery first and then through the center area of ​​the battery, then a good cooling effect cannot be achieved.

[0035] In another illustrative example, taking the fixed flow direction of the liquid passing through the center area of ​​the battery first and then through the edge area of ​​the battery as an example, since the temperature of the center area of ​​the battery pack is usually higher and the temperature of the edge area is lower, although in the high-temperature heat dissipation scenario, the low-temperature liquid passes through the center area of ​​the battery first and then through the edge area of ​​the battery, a better cooling effect can be achieved, but in the low-temperature heating scenario, the high-temperature liquid passes through the center area of ​​the battery first and then through the edge area of ​​the battery, a good heating effect cannot be achieved.

[0036] That is, the battery temperature distribution trends are opposite in the two scenarios of high-temperature heat dissipation and low-temperature heating. Therefore, the fixed liquid flow direction cannot perform differential cooling on batteries with different temperature distributions, resulting in the heating / cooling performance not being able to reach the optimal level at the same time.

[0037] Based on this, the embodiment of the present application adds a reversing valve body in the battery thermal management system, and controls the valve body position of the reversing valve body through the controller according to the thermal management mode to change the flow direction of the liquid in the heat exchanger, thereby achieving heating of the edge area of ​​the battery and then the center area of ​​the battery in the heating mode, and cooling of the center area of ​​the battery and then the edge area of ​​the battery in the cooling mode, which not only ensures the battery heating effect, but also ensures the battery cooling effect, optimizes the battery performance, and improves the utilization rate of the battery energy.

[0038] The battery thermal management system proposed in this application will be described below through specific embodiments.

[0039] Please refer to Figure 1 , which shows a structural block diagram of a battery thermal management system provided by an exemplary embodiment of the present application.

[0040] like Figure 1 As shown, the battery thermal management system includes a battery pack 110, a liquid inlet 120, a liquid outlet 130 and a controller (not shown). A heat exchanger 140 and a reversing valve body 150 are arranged inside the battery pack 110. The heat exchanger 140 includes a first heat exchanger port 1401 and a second heat exchanger port 1402.

[0041] Optionally, the heat exchanger 140 is used to cool or heat the battery pack 110 .

[0042] In one possible implementation, after the thermal management mode is activated, liquid enters the heat exchanger and transfers heat evenly, thereby reducing the temperature gradient inside the battery pack and achieving cooling or heating of the battery pack.

[0043] Optionally, during the cooling process, the cryogenic liquid enters the heat exchanger and flows through the battery, absorbing the heat generated inside the battery, so that the temperature of the cryogenic liquid rises and flows out of the heat exchanger. In order to achieve cyclic cooling, the cryogenic liquid with the increased temperature can flow into the radiator, thereby reducing the temperature through heat exchange and becoming a cryogenic liquid again to enter the heat exchanger.

[0044] Optionally, during the heating process, the high-temperature liquid enters the heat exchanger and flows through the battery to transfer heat to the battery, thereby increasing the battery temperature. In order to achieve cyclic heating, the high-temperature liquid after the temperature is reduced can be heated by the heater and then become high-temperature liquid again and enter the heat exchanger.

[0045] Optionally, the controller is used to control the valve body position of the reversing valve body 150 based on the thermal management mode, and the valve body position includes a cooling position and a heating position.

[0046] In a possible implementation, in order to achieve different liquid flow directions in the heat exchanger under different thermal management modes, the valve body position of the reversing valve body may be controlled by a controller according to the thermal management mode.

[0047] Optionally, the controller may be a battery management system (BMS), that is, the battery management system controls the valve body position of the reversing valve body.

[0048] Optionally, the valve body position includes a cooling position and a heating position.

[0049] In a possible implementation, the battery management system determines the thermal management mode corresponding to the battery pack according to the current battery temperature. Optionally, when the battery pack temperature is too high, high-temperature heat dissipation treatment is required, so the controller needs to control the reversing valve body to be set to the cooling gear; when the battery pack is in a low-temperature environment for a long time, low-temperature heating treatment is required, so the controller needs to control the reversing valve body to be set to the heating gear.

[0050] Optionally, the real-time temperature of the battery pack can be collected and obtained based on a temperature sensor installed on the battery pack. Optionally, when the actual temperature of the battery pack is greater than a first temperature threshold, it indicates that the battery pack temperature is too high and high-temperature heat dissipation treatment is required; when the actual temperature of the battery pack is less than a second temperature threshold, it indicates that the battery pack temperature is too low and low-temperature heating treatment is required. The first temperature threshold and the second temperature threshold can be values ​​pre-set by the designer or values ​​determined based on the actual ambient temperature, which is not limited in the embodiments of the present application.

[0051] Among them, in the cooling gear, the liquid inlet is connected to the first heat exchanger port through the reversing valve body, and the liquid outlet is connected to the second heat exchanger port through the reversing valve body; in the heating gear, the liquid inlet is connected to the second heat exchanger port through the reversing valve body, and the liquid outlet is connected to the first heat exchanger port through the reversing valve body. That is, two pipeline connection methods are set through the reversing valve body, thereby changing the liquid flow direction in the heat exchanger in the heating mode and the cooling mode.

[0052] Indicative, Figure 2 A schematic diagram of adjusting the flow direction of liquid through a reversing valve body provided by an exemplary embodiment of the present application is shown.

[0053] In the cooling gear, the liquid inlet 120 is connected to the first heat exchanger port 1401 through the reversing valve body 150, and the liquid outlet 130 is connected to the second heat exchanger port 1402 through the reversing valve body 150. Thus, the low-temperature liquid enters the battery pack 110 from the liquid inlet 120, passes through the reversing valve body 150, and enters the heat exchanger 140 through the first heat exchanger port 1401, first flows through the battery center area, and then flows to the battery edge area. That is, the battery center area is cooled first, then the battery edge area is cooled, and finally flows out from the second heat exchanger port 1402, passes through the reversing valve body 150, and then flows out of the battery pack 110 from the liquid outlet 130.

[0054] In the heating gear, the liquid inlet 120 is connected to the second heat exchanger port 1402 through the reversing valve body 150, and the liquid outlet 130 is connected to the first heat exchanger port 1401 through the reversing valve body 150. Thus, the high-temperature liquid enters the battery pack 110 from the liquid inlet 120, passes through the reversing valve body 150, and enters the heat exchanger 140 through the second heat exchanger port 1402, first flows through the edge area of ​​the battery, and then flows to the center area of ​​the battery. That is, the edge area of ​​the battery is heated first, then the center area of ​​the battery is heated, and finally flows out from the first heat exchanger port 1401, passes through the reversing valve body 150, and then flows out of the battery pack 110 from the liquid outlet 130.

[0055] To summarize, in the embodiment of the present application, a reversing valve body is additionally provided in the battery thermal management system, and the valve body position of the reversing valve body is controlled by the controller according to the thermal management mode to change the flow direction of the liquid in the heat exchanger, thereby achieving heating of the edge area of ​​the battery and then the center area of ​​the battery in the heating mode, and cooling of the center area of ​​the battery and then the edge area of ​​the battery in the cooling mode, which ensures both the heating and cooling effects of the battery, optimizes the battery performance, and improves the utilization rate of the battery energy.

[0056] In some embodiments, in order to change the flow direction of the liquid in the heat exchanger through the reversing valve body, an adjustable piston may be provided in the pipeline in the reversing valve body, so that the flow direction of the pipeline in the reversing valve body can be changed by controlling the movement of the piston. This method will be described below through specific embodiments.

[0057] Please refer to Figure 3 , which shows a schematic diagram of the internal structure of a reversing valve body provided by an exemplary embodiment of the present application.

[0058] like Figure 3 As shown, the reversing valve body 310 includes a first piston 321 and a second piston 322 , and the first piston 321 and the second piston 322 are located in the valve body main passage 331 of the reversing valve body 310 .

[0059] like Figure 3 As shown, the reversing valve body 310 further includes a first branch 333, a second branch 332 and a third branch 334, and the first branch 333, the second branch 332 and the third branch 334 are all connected to the valve body main line 331. In addition, the liquid inlet 341 is connected to the valve body main line 331, the liquid outlet 342 is connected to the valve body main line 331, the first heat exchanger port 351 is connected to the first branch 333, the second heat exchanger port 352 is connected to the second branch 332, and the second heat exchanger port 352 is connected to the third branch 334.

[0060] Optionally, the first piston 321 and the second piston 322 can move axially in the left-right direction in the valve body main passage 331. That is, by adjusting the positions of the first piston 321 and the second piston 322 in the valve body main passage 331, the flow direction of the liquid in the reversing valve body 310 can be adjusted, thereby adjusting the flow direction of the liquid in the heat exchanger connected to the reversing valve body 310.

[0061] Optionally, the controller is used to control the first piston and the second piston to perform axial movement in the main passage of the valve body based on the thermal management mode to switch the valve body gear position.

[0062] In a possible implementation, in order to flexibly adjust the liquid flow direction in each branch in the reversing valve body, the controller can control the first piston and the second piston to move axially in the main valve body according to the thermal management mode, thereby switching the valve body gear.

[0063] Optionally, the controller is used to control the first piston and the second piston to move from the first position to the second position along the first axis direction in the main passage of the valve body when the thermal management mode is switched from the heating mode to the cooling mode.

[0064] In the cooling gear, the liquid enters the main line of the valve body from the liquid inlet, flows to the first heat exchanger port through the first branch, and enters the heat exchanger through the first heat exchanger port; the liquid flows out of the heat exchanger through the second heat exchanger port, enters the third branch, and flows out from the liquid outlet through the main line of the valve body.

[0065] That is, when the liquid enters the heat exchanger from the first heat exchanger port, the liquid can flow along the heat exchanger from the central area to the edge area of ​​the battery pack, and flow out of the heat exchanger through the second heat exchanger port.

[0066] Indicative, Figure 4 A schematic diagram of adjusting the flow direction of liquid by controlling a piston provided by an exemplary embodiment of the present application is shown.

[0067] When the thermal management mode is switched from the heating mode to the cooling mode, the first piston 421 and the second piston 422 in the reversing valve body 410 move to the right in the valve body main channel 431. At this time, the first piston 421 and the second piston 422 are located in the second position, so that the first piston 421 blocks the connection between the valve body main channel 431 and the second branch channel 432. Only the first branch channel 433 and the third branch channel 434 are connected to the valve body main channel 431.

[0068] In the cooling mode, the low-temperature liquid enters the valve body main channel 431 from the liquid inlet 441, flows to the first heat exchanger port 451 through the first branch channel 433, and then enters the heat exchanger 460 through the first heat exchanger port 451, and starts to flow from the central area of ​​the battery pack 400, first cooling the central area of ​​the battery pack 400, and then cooling the edge area of ​​the battery pack 400, and finally flows out of the heat exchanger 460 through the second heat exchanger port 452, enters the third branch channel 434, and flows out from the liquid outlet 442 through the valve body main channel 431.

[0069] Optionally, the controller is used to control the first piston and the second piston to move from the second position to the first position in the main passage of the valve body in the opposite direction of the first axis when the thermal management mode is switched from the cooling mode to the heating mode.

[0070] In the heating position, the liquid enters the main line of the valve body from the liquid inlet, flows to the second heat exchanger port through the second branch, and enters the heat exchanger through the second heat exchanger port; the liquid flows out of the heat exchanger through the first heat exchanger port, enters the first branch, and flows out from the liquid outlet through the main line of the valve body.

[0071] That is, when the liquid enters the heat exchanger from the second heat exchanger port, the liquid can flow along the heat exchanger from the edge area to the center area of ​​the battery pack, and flow out of the heat exchanger through the first heat exchanger port.

[0072] Indicative, Figure 5 A schematic diagram of adjusting the flow direction of liquid by controlling a piston provided by another exemplary embodiment of the present application is shown.

[0073] When the thermal management mode is switched from cooling mode to heating mode, the first piston 521 and the second piston 522 in the reversing valve body 510 move to the left in the valve body main channel 531. At this time, the first piston 521 and the second piston 522 are located in the first position, so that the second piston 522 blocks the connection between the valve body main channel 531 and the third branch channel 534. Only the first branch channel 533 and the second branch channel 532 are connected to the valve body main channel 531.

[0074] In the heating mode, high-temperature liquid enters the valve body main channel 531 from the liquid inlet 541, flows to the second heat exchanger port 552 through the second branch channel 532, and then enters the heat exchanger 560 through the second heat exchanger port 552, and starts to flow from the edge area of ​​the battery pack 500, first heating the edge area of ​​the battery pack 500, and then heating the center area of ​​the battery pack 500, and finally flows out of the heat exchanger 560 through the first heat exchanger port 551, enters the first branch channel 533, and flows out from the liquid outlet 542 through the valve body main channel 531.

[0075] In the above embodiment, a first piston and a second piston are provided in the reversing valve body, and the connection relationship between the branches in the reversing valve body is changed by adjusting the positions of the first piston and the second piston in the main channel of the valve body. In the cooling gear, the connection relationship between the main channel of the valve body and the second branch is cut off by the first piston, and in the heating gear, the connection relationship between the main channel of the valve body and the third branch is switched by the second piston, thereby realizing the switching of the liquid flow direction in the reversing valve body, simplifying the switching method of the liquid flow direction, and improving the switching efficiency between the cooling gear and the heating gear.

[0076] And in the cooling gear, low-temperature liquid enters the heat exchanger from the first heat exchanger port, which can first cool the central area of ​​the battery and then the edge area of ​​the battery, that is, first cool the area with higher temperature in the battery pack and then cool the area with lower temperature in the battery pack, thereby ensuring the cooling effect of the battery pack; in the heating gear, high-temperature liquid enters the heat exchanger from the second heat exchanger port, which can first heat the edge area of ​​the battery and then the central area of ​​the battery, that is, first heat the area with lower temperature in the battery pack and then the area with higher temperature in the battery pack, thereby ensuring the heating effect of the battery pack.

[0077] That is, whether cooling or heating, the temperature difference inside the battery can be made as small as possible, which can improve battery consistency, battery power output, battery charging speed, battery energy utilization, winter endurance, and user experience.

[0078] In some embodiments, in order to further optimize the battery thermal management process, the flow rate of the low-temperature / high-temperature liquid can be adjusted according to the actual temperature of the battery pack during the battery cooling or heating process, thereby optimizing the system operating cost while ensuring the cooling and heating effects.

[0079] In one possible implementation, in order to simplify the flow rate control cost, in combination with the cooling gear and the heating gear, the position of the first piston in the main pipeline of the valve body, after the liquid enters the reversing valve body, it flows through the first piston to the first branch or the second branch. Therefore, a flow rate regulating device can be set on the first piston, and the flow rate regulating device can be controlled by the controller to adjust the liquid flow rate in the main pipeline of the valve body.

[0080] Optionally, the controller is also used to control the flow rate regulating device based on the actual temperature of the battery pack to adjust the liquid flow rate in the main line of the valve body.

[0081] In a possible implementation, the controller can obtain the actual temperature of the battery pack according to the temperature sensor installed on the battery pack. When the actual temperature is greater than the first temperature threshold, the battery pack needs to be subjected to high-temperature heat dissipation treatment. In order to optimize the cooling efficiency, the controller can also first calculate the first temperature difference between the actual temperature and the first temperature threshold, and then control the flow rate regulating device according to the first temperature difference. For example, when the first temperature difference is large, the flow rate regulating device is controlled to increase the flow rate of the cryogenic liquid, thereby improving the cooling efficiency; when the first temperature difference is small, the flow rate regulating state is controlled to reduce the flow rate of the cryogenic liquid, thereby saving cooling costs under the premise of effective cooling.

[0082] In another possible implementation, the controller can obtain the actual temperature of the battery pack based on the temperature sensor installed on the battery pack. When the actual temperature is less than the second temperature threshold, the battery pack needs to be heated at a low temperature. In order to optimize the heating efficiency, the controller can also first calculate the second temperature difference between the actual temperature and the second temperature threshold, and then control the flow rate regulating device according to the second temperature difference. For example, when the second temperature difference is large, the flow rate regulating device is controlled to increase the flow rate of the high-temperature liquid, thereby improving the heating efficiency; when the second temperature difference is small, the flow rate regulating state is controlled to reduce the flow rate of the high-temperature liquid, thereby saving heating costs under the premise of effective heating.

[0083] Optionally, the controller can also control the flow rate regulating device according to the liquid properties of the liquid, such as liquid viscosity, specific heat capacity, thermal conductivity, etc., to achieve control of the flow rate of the liquid in the reversing valve body. Optionally, the controller can also control the flow rate regulating device based on other flow rate control adjustments, which is not limited in the embodiments of the present application.

[0084] Indicative, Figure 6 A schematic diagram of a structure of a flow rate regulating device provided by an exemplary embodiment of the present application is shown. A flow rate regulating device 613 is provided on the first piston 611, and the flow rate regulating device 613 is a device that can be retracted inwardly. When the flow rate regulating device 613 is retracted inwardly, the flow rate of the liquid can be increased; when the flow rate regulating device 613 is expanded outwardly, the flow rate of the liquid can be reduced.

[0085] In the cooling gear, the first piston 611 and the second piston 612 in the reversing valve body are located at the second position in the valve body main passage 621. At this time, the first piston 611 blocks the communication between the valve body main passage 621 and the second branch passage 623, and only the first branch passage 622 and the third branch passage 624 are connected to the valve body main passage 621. Therefore, the cryogenic liquid enters the valve body main passage 621 from the liquid inlet 631, flows to the first heat exchanger port 641 through the first branch passage 622, and then enters the heat exchanger through the first heat exchanger port 641, and after flowing through various areas of the battery pack, flows out of the heat exchanger through the second heat exchanger port 642, enters the third branch passage 624, and flows out from the liquid outlet 632 through the valve body main passage 621.

[0086] At this time, since a flow rate regulating device 613 is provided on the first piston 611, when the cryogenic liquid enters the valve body main channel 621 from the liquid inlet 631 and flows into the first branch channel 622, the controller can control the flow rate of the cryogenic liquid by adjusting the contraction degree of the flow rate regulating device 613.

[0087] In the heating gear, the first piston 611 and the second piston 612 in the reversing valve body are located at the first position in the valve body main passage 621. At this time, the second piston 612 blocks the communication between the valve body main passage 621 and the third branch passage 624, and only the first branch passage 622 and the second branch passage 623 are connected to the valve body main passage 621. Therefore, the high-temperature liquid enters the valve body main passage 621 from the liquid inlet 631, flows to the second heat exchanger port 642 through the second branch passage 623, and then enters the heat exchanger through the second heat exchanger port 642. After flowing through various areas of the battery pack, the high-temperature liquid flows out of the heat exchanger through the first heat exchanger port 641, enters the first branch passage 622, and flows out from the liquid outlet 632 through the valve body main passage 621.

[0088] At this time, since a flow rate regulating device 613 is provided on the first piston 611, when the high-temperature liquid enters the valve body main channel 621 from the liquid inlet 631 and flows into the second branch 623, the controller can control the flow rate of the high-temperature liquid by adjusting the contraction degree of the flow rate regulating device 613.

[0089] In the above embodiment, by providing a flow rate regulating device on the first piston in the reversing valve body, it is possible to adjust the flow rate of the liquid in the reversing valve body according to the actual temperature of the battery pack, thereby changing the flow rate of the liquid entering the heat exchanger, thereby further optimizing the system operating cost of the thermal management system while ensuring the cooling and heating efficiency, and improving the thermal management quality of the battery pack.

[0090] Please refer to Figure 7 , which shows a flow chart of a control method provided by an exemplary embodiment of the present application. The method is used in a battery thermal management system, wherein the battery thermal management system includes a battery pack, a controller, a liquid inlet and a liquid outlet, a heat exchanger and a reversing valve body are arranged inside the battery pack, and the heat exchanger includes a first heat exchanger port and a second heat exchanger port. The method includes the following steps:

[0091] Step 701, cooling or heating the battery pack through a heat exchanger.

[0092] In a possible implementation, after the thermal management mode is activated, the battery thermal management system cools or heats the battery pack through a heat exchanger. Optionally, after the liquid enters the heat exchanger, the temperature gradient inside the battery pack can be reduced by evenly transferring heat, thereby achieving cooling or heating of the battery pack.

[0093] Optionally, during the cooling process, the cryogenic liquid enters the heat exchanger and flows through the battery, absorbing the heat generated inside the battery, so that the temperature of the cryogenic liquid rises and flows out of the heat exchanger. In order to achieve cyclic cooling, the cryogenic liquid with the increased temperature can flow into the radiator, thereby reducing the temperature through heat exchange and becoming a cryogenic liquid again to enter the heat exchanger.

[0094] Optionally, during the heating process, the high-temperature liquid enters the heat exchanger and flows through the battery to transfer heat to the battery, thereby increasing the battery temperature. In order to achieve cyclic heating, the high-temperature liquid after the temperature is reduced can be heated by the heater and then become high-temperature liquid again and enter the heat exchanger.

[0095] Step 702: Based on the thermal management mode, the valve body position of the reversing valve body is controlled by a controller, and the valve body position includes a cooling position and a heating position.

[0096] In some embodiments, in order to achieve different liquid flow directions in the heat exchanger under different thermal management modes, the battery thermal management system can control the valve body position of the reversing valve body through a controller according to the thermal management mode.

[0097] In a possible implementation, the controller may determine the thermal management mode corresponding to the battery pack based on the current battery temperature of the battery pack, so that when the battery pack requires high-temperature heat dissipation, the reversing valve body is controlled to be set to the cooling position; when the battery pack requires low-temperature heating, the reversing valve body is controlled to be set to the heating position.

[0098] Optionally, in the cooling gear, the liquid inlet is connected to the first heat exchanger port through the reversing valve body, and the liquid outlet is connected to the second heat exchanger port through the reversing valve body. Thus, the low-temperature liquid enters the battery pack from the liquid inlet, passes through the reversing valve body, and enters the heat exchanger through the first heat exchanger port, first flows through the center area of ​​the battery, and then flows to the edge area of ​​the battery. That is, the center area of ​​the battery is cooled first, then the edge area of ​​the battery is cooled, and finally flows out from the second heat exchanger port, passes through the reversing valve body, and then flows out of the battery pack from the liquid outlet.

[0099] Optionally, in the heating gear, the liquid inlet is connected to the second heat exchanger port through the reversing valve body, and the liquid outlet is connected to the first heat exchanger port through the reversing valve body. Thus, the high-temperature liquid enters the battery pack from the liquid inlet, passes through the reversing valve body, and enters the heat exchanger through the second heat exchanger port, first flows through the edge area of ​​the battery, and then flows to the center area of ​​the battery. That is, the edge area of ​​the battery is heated first, then the center area of ​​the battery is heated, and finally flows out from the first heat exchanger port, passes through the reversing valve body, and then flows out of the battery pack from the liquid outlet.

[0100] To summarize, in the embodiment of the present application, a reversing valve body is additionally provided in the battery thermal management system, and the valve body position of the reversing valve body is controlled by the controller according to the thermal management mode to change the flow direction of the liquid in the heat exchanger, thereby achieving heating of the edge area of ​​the battery and then the center area of ​​the battery in the heating mode, and cooling of the center area of ​​the battery and then the edge area of ​​the battery in the cooling mode, which ensures both the heating and cooling effects of the battery, optimizes the battery performance, and improves the utilization rate of the battery energy.

[0101] The solutions shown in the above embodiments of the present application can be applied to electric vehicles. Specifically, the present application also provides an electric vehicle, which includes a battery thermal management system as shown in the above embodiments.

[0102] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0103] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A battery thermal management system, characterized in that: The system includes a battery pack, a controller, a liquid inlet and a liquid outlet. A heat exchanger and a reversing valve body are arranged inside the battery pack. The heat exchanger includes a first heat exchanger port and a second heat exchanger port. The heat exchanger is used to cool or heat the battery pack; The controller is used to control the valve body position of the reversing valve body based on the thermal management mode, and the valve body position includes a cooling position and a heating position; Wherein, in the cooling gear, the liquid inlet is connected to the first heat exchanger port through the reversing valve body, and the liquid outlet is connected to the second heat exchanger port through the reversing valve body; in the heating gear, the liquid inlet is connected to the second heat exchanger port through the reversing valve body, and the liquid outlet is connected to the first heat exchanger port through the reversing valve body.

2. The system according to claim 1, characterized in that The reversing valve body comprises a first piston and a second piston, wherein the first piston and the second piston are located in a main valve body passage of the reversing valve body; The reversing valve body further comprises a first branch, a second branch and a third branch, wherein the first branch, the second branch and the third branch are all connected to the main branch of the valve body; Wherein, the liquid inlet is connected to the main line of the valve body, the liquid outlet is connected to the main line of the valve body, the first heat exchanger port is connected to the first branch, the second heat exchanger port is connected to the second branch, and the second heat exchanger port is connected to the third branch; The controller is used to control the first piston and the second piston to perform axial movement in the main passage of the valve body based on the thermal management mode, so as to switch the gear position of the valve body.

3. The system according to claim 2, characterized in that The controller is used to: When the thermal management mode is switched from the heating mode to the cooling mode, the first piston and the second piston are controlled to move from a first position to a second position along a first axis direction in the main passage of the valve body.

4. The system according to claim 3, characterized in that In the cooling position, Liquid enters the main passage of the valve body from the liquid inlet, flows to the first heat exchanger port through the first branch, and enters the heat exchanger through the first heat exchanger port; The liquid flows out of the heat exchanger through the second heat exchanger port, enters the third branch, and flows out of the liquid outlet through the valve body main line.

5. The system according to claim 2, characterized in that The controller is used to: When the thermal management mode is switched from the cooling mode to the heating mode, the first piston and the second piston are controlled to move from the second position to the first position in the main passage of the valve body along a direction opposite to the first axis direction.

6. The system according to claim 5, characterized in that In the heating position, Liquid enters the main passage of the valve body from the liquid inlet, flows to the second heat exchanger port through the second branch, and enters the heat exchanger through the second heat exchanger port; The liquid flows out of the heat exchanger through the first heat exchanger port, enters the first branch, and flows out of the liquid outlet through the valve body main line.

7. The system according to claim 2, characterized in that A flow rate regulating device is installed on the first piston; The controller is also used to control the flow rate regulating device based on the actual temperature of the battery pack to adjust the liquid flow rate in the main pipeline of the valve body.

8. The system according to any one of claims 1 to 7, characterized in that: In the cooling gear, the liquid enters the heat exchanger from the first heat exchanger port, flows along the heat exchanger from the central area to the edge area of ​​the battery pack, and flows out of the heat exchanger through the second heat exchanger port; In the heating gear, the liquid enters the heat exchanger from the second heat exchanger port, flows along the heat exchanger from the edge area to the center area of ​​the battery pack, and flows out of the heat exchanger through the first heat exchanger port.

9. A control method, characterized in that: The method is used for the battery thermal management system, which includes a battery pack, a controller, a liquid inlet and a liquid outlet. A heat exchanger and a reversing valve body are arranged inside the battery pack, and the heat exchanger includes a first heat exchanger port and a second heat exchanger port; The method comprises: Cooling or heating the battery pack by means of the heat exchanger; Based on the thermal management mode, the controller controls the valve body position of the reversing valve body, wherein the valve body position includes a cooling position and a heating position; Wherein, in the cooling gear, the liquid inlet is connected to the first heat exchanger port through the reversing valve body, and the liquid outlet is connected to the second heat exchanger port through the reversing valve body; in the heating gear, the liquid inlet is connected to the second heat exchanger port through the reversing valve body, and the liquid outlet is connected to the first heat exchanger port through the reversing valve body.

10. An electric vehicle, characterized in that: The electric vehicle comprises a battery thermal management system as claimed in any one of claims 1 to 8.

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